An image forming apparatus includes an image transfer unit that transfers a reversal image based on a scanned document image onto an image bearing member as a toner image and a secondary transfer unit that comes into contact with the image bearing member and transfers the toner image onto a recording medium.
The secondary transfer unit includes a contact and separation mechanism for bringing a secondary transfer roller into contact with the image bearing member when the toner image is transferred onto a sheet and separating the secondary transfer roller from the image bearing member when the toner image is not transferred onto the sheet.
There is known a secondary transfer roller contact and separation driving apparatus in which, in a secondary transfer unit having a mechanism for bringing a secondary transfer roller into contact with and separating the secondary transfer roller from an image bearing member, the number of components of a mechanical unit configuring a mechanism for performing contact and separation operations is not increased and a device such as an electromagnetic clutch that requires electric control is not used (see JP-A-2007-264546).
On the other hand, there is known an image forming apparatus mounted with a mechanism for bringing a cleaning blade into contact with a secondary transfer roller and cleaning the secondary transfer roller in order to scrape off a toner on the secondary transfer roller. Further, there is known a mechanism for applying a lubricant to the surface of a secondary transfer roller via a fur brush (a lubricant applying brush) in order to extend the durable life of the secondary transfer roller and prevent the cleaning blade from curling up. Solid zinc stearate is used as the lubricant. The zinc stearate is mounted on a holding member and pressed to the fur brush side by a spring. The holding member is formed of a member having high rigidity such as a sheet metal and is integrated with the zinc stearate to configure a lubricant assembly.
When the lubricant is supplied in this way, if an application amount of the lubricant is excessive, it is likely that rear stain of a sheet occurs. If the application amount is too small, for example, the cleaning blade curls up and a load on the secondary transfer roller increases.